The present invention relates to an electrically driven aperture-setting device.
Some types of photographic and television cameras have employed an exposure control system of the type in which aperture is varied so as to control the amount of light from an object. In this case, aperture-setting devices are driven by an electric motor or a combination of permanent magnets and an electromagnet. As a result, they are all large in size and consequently not easy to handle. In addition, they generally maintain a predetermined aperture by the balance of magnetic forces. Therefore, if a television camera is mounted on an automotive vehicle, vibrations of the vehicle are transmitted to the camera, so that it becomes extremely difficult to maintain a desired aperture.